Rudder control pedal assembly with linear pedal travel path

ABSTRACT

A rudder control apparatus includes a pair of pedal assemblies, coupled to a support frame for control of a rudder control device. Each one of the pedal assemblies includes an idler link, a coupler link, and a drive link. The idler link is coupled to the support frame and is pivotable relative to the support frame. The coupler link is coupled to the idler link and is pivotable relative to the idler link. The drive link is coupled to the coupler link and to the support frame and is pivotable relative to the coupler link and relative to the support frame. A pedal is coupled to the coupler link. A four-bar linkage is formed by the support frame, the idler link, the coupler link, and the drive link and confines movement of the pedal to a linear travel path in a forward direction and a rearward direction.

FIELD

This application relates to rudder control and, more particularly, torudder control pedal assemblies.

BACKGROUND

Modern aircraft include various flight control surfaces that allow apilot to adjust and control the aircraft's flight attitude. Controlsurfaces are movably connected to the aircraft. For example, theempennage of an aircraft typically includes a vertical stabilizer and arudder moveable (side-to-side movement) relative to the verticalstabilizer. Actuation and resulting motion of the rudder causes acorresponding yaw motion of the aircraft that readjusts the aircraft'sflight attitude.

Rudder actuation is typically effected by a pair of pedals positioned atthe pilot's feet. The pedals are interconnected such that when one pedalis pushed away from the pilot, the other pedal concomitantly movestoward the pilot. The direction of rudder movement depends on whichpedal is being pushed.

Traditionally, rudder control pedals are pivotally connected to theaircraft at pivot points located above or below the pilot interface.Therefore, when displaced, the pedals travel through an arcuate paththat is dictated, at least in part, by the distance between the pedalsand the pivot points. Such arcuate pedal travel paths can beergonomically awkward, particularly for pilots of relatively tallstature and pilots of relatively short stature. Existing attempts toprovide a linear pedal travel path have various drawbacks, such as useof mechanically unreliable sliding mechanisms and excessivelylarge/complex assemblies.

Accordingly, those skilled in the art continue with research anddevelopment efforts in the field of rudder control.

SUMMARY

In one example, the disclosed rudder control apparatus may include alaterally spaced apart pair of pedal assemblies each coupled to asupport frame and a rudder control device, the pedal assemblies eachincluding a four-bar linkage constrained to movement in an approximatelyvertical plane, and a pedal coupled to the four-bar linkage andconstrained to movement in an approximately horizontal plane.

In one example, the disclosed rudder control pedal assembly may includean idler link pivotably coupled to a support frame at a first joint, acoupler link pivotably coupled to the idler link at a second joint, adrive link pivotably coupled to the coupler link at a third joint andpivotably coupled to the support frame at a fourth joint, and a pedalcoupled to the coupler link and constrained to movement along anapproximately linear travel path, wherein the support frame forms animaginary fixed link to complete a four-bar linkage.

In one example, the disclosed aircraft may include an airframe includinga support frame and rudder for control of yaw motion, a rudder controldevice operatively coupled to the rudder for control of side-to-sidemotion of the rudder, and a laterally spaced apart pair of pedalassemblies each coupled to the support frame and the rudder controldevice, the pedal assemblies each including a four-bar linkageconstrained to movement in an approximately vertical plane, and a pedalcoupled to the four-bar linkage and constrained to movement in anapproximately horizontal plane.

Other examples of the disclosed rudder control apparatus and ruddercontrol pedal assembly with linear pedal travel path will becomeapparent from the following detailed description, the accompanyingdrawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic isometric view of one example of an aircraftincorporating the disclosed rudder control apparatus;

FIG. 2 is a schematic isometric view of one example of the disclosedrudder control apparatus with pedal assemblies in a neutral position;

FIG. 3 is a schematic isometric view of the rudder control apparatus ofFIG. 2 with a right one of the pedal assemblies in a forward position;

FIG. 4 is a schematic isometric view of the rudder control apparatus ofFIG. 2 with a left one of the pedal assemblies in the forward position;

FIG. 5 is a schematic side elevation view of one example of thedisclosed rudder control apparatus;

FIG. 6A is a schematic side elevation view of one example of thedisclosed rudder control apparatus with the pedal assemblies in theneutral position and illustrating an approximately linear travel path ofthe pedals;

FIG. 6B is a schematic side elevation view of the disclosed ruddercontrol apparatus of FIG. 6A with the left one of the pedal assembliesin the forward position and illustrating the approximately linear travelpath of the pedals;

FIG. 6C is a schematic side elevation view of the disclosed ruddercontrol apparatus of FIG. 6A with the right one of the pedal assembliesin the forward position and illustrating the approximately linear travelpath of the pedals;

FIG. 7 is flow diagram of an aircraft manufacturing and servicemethodology; and

FIG. 8 is a block diagram of an aircraft.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings,which illustrate specific examples described by the disclosure. Otherexamples having different structures and operations do not depart fromthe scope of the present disclosure. Like reference numerals may referto the same feature, element or component in the different drawings.

Unless otherwise indicated, the terms “first,” “second,” etc. are usedherein merely as labels, and are not intended to impose ordinal,positional, or hierarchical requirements on the items to which theseterms refer. Moreover, reference to a “second” item does not require orpreclude the existence of lower-numbered item (e.g., a “first” item)and/or a higher-numbered item (e.g., a “third” item).

Reference herein to “example,” “one example,” “another example,” orsimilar language means that one or more feature, structure, element,component or characteristic described in connection with the example isincluded in at least one embodiment or implementation. Thus, the phrases“in one example,” “as one example,” and similar language throughout thepresent disclosure may, but do not necessarily, refer to the sameexample. Further, the subject matter characterizing any one example may,but does not necessarily, include the subject matter characterizing anyother example.

Illustrative, non-exhaustive examples, which may be, but are notnecessarily, claimed, of the subject matter according the presentdisclosure are provided below.

Referring to FIG. 1, which illustrates one example of aircraft 100incorporating the disclosed rudder control apparatus 200. Aircraft 100may include a forward cockpit 102 (e.g., pilot station) and tailassembly 104. Tail assembly 104 may include vertical stabilizer 110 andrudder 108 movably (e.g., pivotably) coupled to vertical stabilizer 110.Rudder control apparatus 200 is located within cockpit 102 at a positionsuitable for access and operation by the feet of a pilot. Rudder controlapparatus 200 includes two pedal assemblies 202 operatively coupled torudder control device 106. Rudder control device 106 is operativelycoupled to and controls movement (e.g., side-to-side movement) of rudder108 to correspondingly cause yaw motion of aircraft 100.

As one example, rudder control device 106 may include a mechanicalactuation mechanism mechanically (e.g., directly) coupled to rudder 108.For example, actuation of the rudder control device 106 by ruddercontrol apparatus 200 (e.g., forward and aft motion of pedal assemblies202) would physically cause movement of rudder 108. Movement of rudder108 may be directly proportional to the displacement of pedal assemblies202. As another example, rudder control device 106 may include anelectronic actuation mechanism electrically coupled to rudder actuators(e.g., by electric wires) coupled to rudder 108. For example, ruddercontrol device 106 may include one or more sensors capable of detectingforward and aft motion of pedal assemblies 202 and a processor capableof generating and transmitting control (e.g., electrical) signals inresponse to motion of pedal assemblies 202. The strength of the controlsignal may be directly proportional to the displacement of pedalassemblies, which in turn control movement of rudder 108.

Referring to FIGS. 2-4, one example of rudder control apparatus 200,hereinafter referred to generally as apparatus 200, is disclosed.Apparatus 200 includes a laterally spaced apart pair of pedal assemblies202. Each one of pedal assemblies 202 may be coupled to support frame112 and to rudder control device 106. Each one (e.g., a first one orleft one and a second one or right one) of pedal assemblies 202 may bealso identified individually in FIGS. 3 and 4 as left pedal assembly 202a and right pedal assembly 202 b. Each one of pedal assemblies 202 mayinclude four-bar linkage 204. Each one (e.g., a first one or a left oneand a second one or a right one) of four-bar linkages may also beidentified individually in FIGS. 3 and 4 as left four-bar linkage 204 aand right four-bar linkage 204 b. Each one of four-bar linkages 204 maybe constrained to movement in an approximately vertical plane (e.g., aplane approximately parallel to an Y, Z-plane formed by a Y-axis and aZ-axis) (FIG. 2). Each one of pedal assemblies 202 may include pedal 206coupled to four-bar linkage 204. Each one (e.g., a first one or a leftone and a second one or a right one) of pedals 206 may also beidentified individually in FIGS. 3 and 4 as left pedal 206 a and rightpedal 206 b. Each one of pedals 206 may be constrained to movement in anapproximately horizontal plane (e.g., a plane approximately parallel toan X, Y-plane formed by an X-axis and the Y-axis) (FIG. 2).

Each one of pedal assemblies 202 may be interconnected, for example, byrudder bar 114 pivoted at its center, so that when one of pedals 206moves in a forward direction (e.g., is pushed away from the pilot) theother one of pedals 206 moves in an aft direction (e.g., toward thepilot). Rudder bar 114 may be connected to or may form a part of ruddercontrol device 106. FIG. 2 illustrates each one of pedal assemblies 202in a neutral position. FIG. 3 illustrates the right one of pedalassemblies 202 (e.g., right pedal assembly 202 b) in a forward position(e.g., right pedal 206 b moved away from the pilot) and the left one ofpedal assemblies 202 (e.g., left pedal assembly 202 a) in an aftposition (e.g., left pedal 206 a moved toward the pilot). FIG. 4illustrates the left one of pedal assemblies 202 (e.g., left pedalassembly 202 a) in the forward position (e.g., left pedal 206 a movedaway from the pilot) and a right one of pedal assemblies 202 (e.g.,right pedal assembly 202 b) in the aft position (e.g., right pedal 206 bmoved toward the pilot).

Referring to FIGS. 2-4, in one example, each one of four-bar linkages204 includes idler link 208. Each one (e.g., a first one or a left oneand a second one or a right one) of idler links 208 may also beidentified individually in FIGS. 3 and 4 as left idler link 208 a andright idler link 208 b. Each one of idler links 208 is pivotably coupledto support frame 112 by first joint 214. Each one (e.g., a first one ora left one and a second one or a right one) of first joints 214 may alsobe identified individually in FIGS. 3 and 4 as left first joint 214 aand right first joint 214 b.

Each one of four-bar linkages 204 includes coupler link 210. Each one(e.g., a first one or a left one and a second one or a right one) ofcoupler links 210 may also be identified individually in FIGS. 3 and 4as left coupler link 210 a and right coupler link 210 b. Each one ofcoupler links 210 is pivotably coupled to idler link 208 at second joint216. Each one (e.g., a first one or a left one and a second one or aright one) of second joints 216 may also be identified individually inFIGS. 3 and 4 as left second joint 216 a and right second joint 216 b.

Each one of four-bar linkages 204 includes drive link 212. Each one(e.g., a first one or a left one and a second one or a right one) ofdrive links 212 may also be identified individually in FIGS. 3 and 4 asleft drive link 212 a and right drive link 212 b. Each one of drivelinks 212 is pivotably coupled to coupler link 210 at third joint 218and pivotably coupled to support frame 112 at fourth joint 220. Each one(e.g., a first one or a left one and a second one or a right one) ofthird joints 218 may also be identified individually in FIGS. 3 and 4 asleft third joint 218 a and right third joint 218 b. Each one (e.g., afirst one or a left one and a second one or a right one) of fourthjoints 220 may also be identified individually in FIGS. 3 and 4 as leftfourth joint 220 a and right fourth joint 220 b.

Referring to FIG. 5, and with reference to FIGS. 1-4, support frame 112forms an imaginary fixed (e.g., ground) link 234 to complete each one offour-bar linkages 204. Thus, idler link 208, coupler link 210, and drivelink 212 combine with fixed link 234 formed by support frame 112 betweenfirst joint 214 and fourth joint 220 (FIGS. 2-4) to create four-barlinkage 204. As one example, support frame 112 may include (e.g., beformed by) a portion of an airframe of aircraft 100 (FIG. 1). As anotherexample, support frame 112 may include (e.g., be formed by) a structuralportion of cockpit 102 (FIG. 1).

Referring to FIG. 5, and with reference to FIGS. 2-4, each one of idlerlinks 208 includes idler link-first end 222 and idler link-second end224 opposite idler link-first end 222. Each one of coupler links 210includes coupler link-first end 226 and couple link-second end 228opposite coupler link-first end 226. Each one of drive links 212includes drive link-first end 230 and drive link-second end 232 oppositedrive link-first end 230.

Idler link-first end 222 is pivotably coupled to support frame 112(forming first joint 214). Coupler link-first end 226 is pivotablycoupled to idler link-second end 224 (forming second joint 216). Drivelink-first end 230 is pivotably coupled to an intermediate location ofcoupler link 210 spaced away from and disposed between couplerlink-first end 226 and coupler-link-second end 228 (forming third joint218). Drive link 212 is pivotably coupled to support frame 112 at anintermediate location spaced away from and disposed between drivelink-first end 230 and drive link-second end 232.

In one example, each one of coupler links 210 includes couplerlink-connection portion 236 and coupler link-extension portion 238.Coupler link-connection portion 236 may be formed (e.g., defined by aportion of coupler link 210) between coupler link-first end 226 andthird joint 218 (the location of the pivot connection between couplerlink 210 and drive link-first end 230). Coupler link-extension portion238 may be formed (e.g., defined by another portion of coupler link 210)between third joint 218 and coupler link-second end 228. Each one (e.g.,a first one or left one and a second one or right one) of couplerlink-connection portions 236 may also be identified in FIGS. 3 and 4 asleft coupler link-connection portion 236 a and right couplerlink-connection portion 236 b. Each one (e.g., a first one or left oneand a second one or right one) of coupler link-extension portions 238may also be identified in FIGS. 3 and 4 as left coupler link-extensionportion 238 a and right coupler link-extension portion 238 b.

In one example, each one of drive links 212 includes drivelink-connection portion 240 and drive link-extension portion 242 (FIG.2). Drive link-connection portion 240 may be formed (e.g., defined by aportion of drive link 212) between drive link-first end 230 and fourthjoint 220 (the location of the pivot connection between drive link 212and support frame 112). Drive link-extension portion 242 may be formed(e.g., defined by another portion of drive link 212) between fourthjoint 220 and drive link-second end 232. Each one (e.g., a first one orleft one and a second one or right one) of drive link-connectionportions 240 may also be identified in FIGS. 3 and 4 as left drivelink-connection portion 240 a and right drive link-connection portion240 b. Each one (e.g., a first one or left one and a second one or rightone) of drive link-extension portions 242 may also be identified inFIGS. 3 and 4 as left drive link-extension portion 242 a and right drivelink-extension portion 242 b.

Each one of pedals 206 is coupled to coupler link-second end 228 of acorresponding one of coupler links 210. As one example, pedal 206 iscoupled to coupler link 210 at fifth joint 244 proximate (e.g., at ornear) coupler link-second end 228. Pedal 206 may be pivotably coupled tocoupler link 210 at fifth joint 244. Each one (e.g., a first one or aleft one and a second one or a right one) of fifth joints 244 may alsobe identified individually in FIGS. 3 and 4 as left fifth joint 244 aand right fifth joint 244 b.

Drive link-second end 232 of each one of drive links 212 is operativelycoupled to rudder control device 106. In such a configuration, forwardmotion of one of pedals 206 is translated to or is otherwise detected byrudder control device 106 via a forward stroke of an associated one ofpedal assemblies 202 and corresponding motion of an associated one offour-bar linkages 204. As one example, forward motion of pedal 206 alongapproximately linear travel path 248 (FIGS. 6A, 6B and 6C) istranslated, via four-bar-linkage 204, to rearward (e.g., aft) motion ofdrive link-second end 232 in order to affect a control operation ofrudder control device 106.

As one example, rudder control device 106 may include rudder controlpushrod 116. Each one of rudder control pushrods 116 is coupled to acorresponding one of drive links 212 and a corresponding end of rudderbar 114. Each one (e.g., a first one or left one and a second one orright one) of rudder control pushrods 116 may also be identifiedindividually in FIGS. 3 and 4 as left rudder control pushrod 116 a andright rudder control pushrod 116 b. Each one of rudder control pushrods116 may include rudder control pushrod-first end 118 and rudder controlpushrod-second end 120. Rudder control pushrod 116 (e.g., proximaterudder control pushrod-first end 118) may be pivotably coupled to drivelink 212 at sixth joint 246 (e.g., proximate drive link-second end 232).Each one (e.g., a first one or a left one and a second one or a rightone) of sixth joints 246 may also be identified individually in FIGS. 3and 4 as left sixth joint 246 a and right sixth joint 246 b. Ruddercontrol pushrod 116 (e.g., proximate actuation rod-second end 120) maybe coupled to the corresponding end of rudder bar 114.

In one example, and as illustrated in FIG. 3, the forward stroke ofright four-bar linkage 204 b in response to forward motion of rightpedal 206 b (and an opposing rearward stroke of left four-bar linkage204 a) may actuate (e.g., move or pivot) rudder bar 114, which in turncauses side-to-side movement of rudder 108 (FIG. 1) in a firstdirection. Similarly, and as illustrated in FIG. 4, the forward strokeof left four-bar linkage 204 a in response to forward motion of leftpedal 206 a (and the opposing rearward stroke of right four-bar linkage204 b) may actuate rudder bar 114, which in turn causes an opposingside-to-side movement of rudder 108 (FIG. 1) in a second direction.

Referring to FIGS. 6A, 6B and 6C, the stroke (e.g., the forward strokeand rearward stroke) of each one of four-bar linkages 204 provides forforward and rearward movement of pedal 206 along a predefined travelpath 248. Each one of four-bar linkages 204 is constructed such thattravel path 248 is approximately linear (e.g., approximately lineartravel path 248). As one example, linear travel path 248 may beapproximately parallel to the horizontal plane. As another example,linear travel path 248 may be disposed at an angle of at mostapproximately five degrees relative to the horizontal plane. As anotherexample, linear travel path 248 may be disposed at an angle of at mostapproximately ten degrees relative to the horizontal plane. As yetanother example, linear travel path 248 may be disposed at an angle ofat most approximately fifteen degrees relative to the horizontal plane.

In order to provide for the approximately linear travel path 248,various lengths of portions of the links between certain ones of thejoints of four-bar linkage 204 may be set to predefined ratios. In oneexample, a first ratio of length L1 of a portion of coupler link 210between third joint 218 and fifth joint 244 and length L2 of a portionof drive link 212 between third joint and fourth joint 220 areconfigured to provide approximately linear travel path 248 for pedal206. As one example, coupler link-extension portion 236 may definelength L1 and drive link-connection portion 240 may define length L2.

In one example, a second ratio of length L1 of the portion of couplerlink 210 between third joint 218 and fifth joint 244 and length L3 ofanother portion of coupler link 210 between second joint 216 and thirdjoint are configured to provide approximately linear travel path 248 forpedal 206. As one example, coupler link-extension portion 236 may definelength L1 and coupler link-connection portion 236 may define length L3.

In one example, the first ratio of length L1 to length L2 may beapproximately one to one (1:1). In other words, length L1 to length L2may be approximately equal. However, in other examples, the first ratioof length L1 to length L2 may vary by a few percent to several percent.As one example, length L1 and length L2 may within approximatelytwo-and-a-half percent of each other (e.g., length L1 may be up toapproximately two-and-a-half percent greater or less than length L2). Asanother example, length L1 and length L2 may within approximately fivepercent of each other.

In one example, the first ratio of length L1 to length L3 may beapproximately one to one (1:1). In other words, length L1 to length L3may be approximately equal. However, in other examples, the first ratioof length L1 to length L3 may vary by a few percent to several percent.As one example, length L1 and length L3 may be within approximatelytwo-and-a-half percent of each other (e.g., length L1 may be up toapproximately two-and-a-half percent greater or less than length L3). Asanother example, length L1 and length L2 may within approximately fivepercent of each other.

FIGS. 6A, 6B and 6C illustrate approximately linear travel path 248 ofeach one of pedals 206 during the forward and rearward stroke of eachone of four-bar linkages 204 of pedal assemblies 202. FIG. 6Aillustrates apparatus 200 with the left one of pedal assemblies 202(e.g., left pedal assembly 202 a in FIGS. 3 and 4) and the right one ofpedal assemblies 202 (e.g., right pedal assembly 202 b in FIGS. 3 and 4)in the neutral position. FIG. 6B illustrates apparatus 200 with the leftone of pedal assemblies 202 in the forward position and the right one ofpedal assemblies 202 in the rearward position. FIG. 6C illustratesapparatus 200 with the right one of pedal assemblies 202 in the forwardposition and the left one of pedal assemblies 202 in the rearwardposition.

Referring to FIGS. 6A, 6B and 6C, in response to a forward force appliedone of pedals 206, the one of pedals 206 moves forward alongapproximately linear travel path 248 and the other one of pedals 206moves rearward along approximately linear travel path 248. In otherwords, in response to the forward force applied pedal 206, fifth joint244 moves (e.g., forward and rearward) along approximately linear travelpath 248.

Referring to FIGS. 6A, 6B and 6C, in one example implementation, bothpedal assemblies 202 may begin in the neutral position, as illustratedin FIG. 6A. In order to cause side-to-side movement of rudder 108 (FIG.1), the pilot may apply a forward force to one of pedals 206 andinitiate the forward stroke of the associated one of four-bar linkages204, which in turn moves pedal 206 along approximately linear travelpath 248. As described above, since both pedal assemblies 202 areinterconnected through rudder control device 106, the forward stroke ofone of four-bar linkages 204 may in turn cause the rearward stroke ofthe other one of four-bar linkages 204 and rearward movement of theother one of pedals 206, as illustrated in FIGS. 6B and 6C.

In one example, during the forward stroke of four-bar linkage 204 (e.g.,of pedal assembly 202), fifth joint 244 and, thus, pedal 206 move alonglinear travel path 248. Forward movement of pedal 206 (and fifth joint244) causes coupler link 210 to pivot about second joint 216 and idlerlink 208 to pivot about first joint 214. Pivot motion of coupler link210 about second joint 216 moves third joint 218 forward, causes drivelink 212 to pivot about left third joint 218 a and fourth joint 220, andmoves sixth joint 246 rearward. Rearward movement of sixth joint 246 istranslated to pivot motion of rudder bar 114 via a rearward forceapplied by rudder control pushrod 116. During the rearward stroke offour-bar linkage 204 (e.g., of pedal assembly 202), the motionsdescribed above are substantially reversed due to a forward force beingapplied to sixth joint 246 by rudder control pushrod 116.

In addition to the first and second length ratios described above, idlerlink 208 also provides for approximately linear travel path 248 of pedal206. Idler link 208 constrains movement of fifth joint 244 alongapproximately linear travel path 248 by facilitating approximatelyvertical (e.g., up and down) movement of second joint 216 as couplerlink 210 pivots about second joint 216 and second joint 216 pivots aboutfirst joint 214. First joint 214 and fourth joint 220 remain in a fixedposition by support frame 112 throughout the forward and rearward strokeof pedal assembly 202.

Referring to FIGS. 2-6, and with reference to FIG. 1, in one example,each one of pedal assemblies 202 may also provide for control for brakesystem 122 of aircraft 100. In one example, pedal 206 may be pivotablycoupled to coupler link 210 at fifth joint 244 (proximate couplerlink-second end 228). In such a configuration, pivot motion of pedal 206about fifth joint 244 may actuate brake system 122. Each one of pedals206 may operate independently such that the pilot may apply asymmetricbrake pressure to brake system 122.

In one example, each one of pedal assemblies 202 includes pedal crank250. Each one (e.g., a first one or left one and a second one or rightone) of pedal cranks 250 may be individually identified in FIGS. 3 and 4as left pedal crank 250 a and right pedal crank 250 b. Pedal crank 250may be pivotably coupled to coupler link 210 at fifth joint 244 (e.g.,proximate coupler link-second end 228). Pedal 206 may be fixedly coupledto pedal crank 250 such that a force applied to an upper portion ofpedal 206 (e.g., spaced away from fifth joint 244) by the pilot's footis translated to rotation of pedal crank 250 about fifth joint 244. Inother words, the rotational force applied to the upper portion of pedal206 (e.g., away from fifth joint 244) that in turn rotates pedal 206 (orpedal crank 250) about fifth joint 244 to affect brake control isseparate and distinct from the forward force applied to pedal 206 (e.g.,proximate fifth joint 244) that in turn moves pedal 206 forward andactuates four-bar linkage 204 to affect rudder control. Each one ofpedal assemblies 202 may include brake control linkage 252. Each one(e.g., a first one or a left one and a second one or a right one) ofbrake control linkages 252 may also be identified in FIGS. 3 and 4 asleft brake linkage 252 a and right brake linkage 252 b. Each one ofbrake control linkages 252 may include two or more brake control links(not explicitly identified). One end of brake control linkage 252 ispivotably coupled to pedal crank 250, for example, proximate an endthereof (e.g., an end opposite fifth joint 244). An opposing end ofbrake control linkage 252 is pivotably coupled to an end of brakecontrol pushrod 124. Each one (e.g., a first one or a left one and asecond one or a right one) of brake control pushrod 124 may also beidentified in FIGS. 3 and 4 as left brake control pushrod 124 a andright brake control pushrod 124 b. An opposing end of brake controlpushrod 124 may be operative coupled to brake system 122. Thus, rotationof pedal 206 (and pedal crank 250) about fifth joint 244 may bedirection proportional to the brake pressure applied to brake system122.

In one example, the disclosed apparatus 200 may facilitate positionadjustment of pedal 206 of each pedal assembly 202. As one example, theposition of pedal 206 in the neutral position, as illustrated in FIGS. 2and 5, may be adjusted forward or aft, for example, relative to thepilot to accommodate for pilots of different sizes. As one example, therelative location of fourth joint 220 (e.g., the location of the pivotconnection between drive link 212 and support frame 112) may be movedforward or aft. Adjustment of the relative location of fourth joint 220may effectuate a change in the forward/aft position of pedal 206relative to the pilot.

Accordingly, the disclosed rudder control apparatus 200 and ruddercontrol pedal assembly 202 provide for approximately linear travel path248 of the pilot's feet when used to control motion of rudder 108, whichis an ergonomically superior design compared to an arcuate travel path.

Examples of the disclosure may be described in the context of anaircraft manufacturing and service method 400, as shown in FIG. 7, andan aircraft 402, as shown in FIG. 8. During pre-production, the aircraftmanufacturing and service method 400 may include specification anddesign 404 of the aircraft 402 and material procurement 406. Duringproduction, component/subassembly manufacturing 408 and systemintegration 410 of the aircraft 402 takes place. Thereafter, theaircraft 402 may go through certification and delivery 412 in order tobe placed in service 414. While in service by a customer, the aircraft402 is scheduled for routine maintenance and service 416, which may alsoinclude modification, reconfiguration, refurbishment and the like.

Each of the processes of method 400 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof venders, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 8, the aircraft 402 produced by example method 400 mayinclude an airframe 418 with a plurality of systems 420 and an interior422. Examples of the plurality of systems 420 may include one or more ofa propulsion system 424, an electrical system 426, a hydraulic system428, an environmental system 430, and a flight control system 432. Thedisclosed rudder control pedal assembly with linear pedal travel path200 may be included in or form a part of the flight control system 432.Any number of other systems may be included.

The disclosed rudder control pedal assembly with linear pedal travelpath may be employed during any one or more of the stages of theaircraft manufacturing and service method 400. As one example, thedisclosed rudder control pedal assembly with linear pedal travel pathmay be employed during material procurement 406. As another example,components or subassemblies corresponding to component/subassemblymanufacturing 408, system integration 410, and or maintenance andservice 416 may be fabricated or manufactured using the disclosed ruddercontrol pedal assembly with linear pedal travel path. As anotherexample, the airframe 418 and the interior 422 may be constructed usingthe disclosed rudder control pedal assembly with linear pedal travelpath. Also, one or more apparatus examples, method examples, or acombination thereof may be utilized during component/subassemblymanufacturing 408 and/or system integration 410, for example, bysubstantially expediting assembly of or reducing the cost of an aircraft402, such as the airframe 418 and/or the interior 422. Similarly, one ormore of system examples, method examples, or a combination thereof maybe utilized while the aircraft 402 is in service, for example andwithout limitation, to maintenance and service 416.

The disclosed rudder control pedal assembly with linear pedal travelpath is described in the context of an aircraft; however, one ofordinary skill in the art will readily recognize that the disclosedrudder control pedal assembly with linear pedal travel path may beutilized for a variety of applications. For example, the disclosedrudder control pedal assembly with linear pedal travel path may beimplemented in various types of vehicles including, e.g., helicopters,passenger ships, automobiles, construction equipment, farm equipment,tracked vehicles and the like.

Although various embodiments of the disclosed rudder control pedalassembly with linear pedal travel path have been shown and described,modifications may occur to those skilled in the art upon reading thespecification. The present application includes such modifications andis limited only by the scope of the claims.

What is claimed is:
 1. A rudder control apparatus comprising: a pair ofpedal assemblies, each one of said pair of pedal assemblies is coupledto a support frame for control of a rudder control device, and each oneof said pair of pedal assemblies comprises: an idler link coupled tosaid support frame at a first joint, said idler link is pivotablerelative to said support frame about said first joint, and said firstjoint is fixed relative to said support frame; a coupler link coupled tosaid idler link at a second joint, said coupler link is pivotablerelative to said idler link about said second joint, and said secondjoint is movable relative to said support frame; a drive link coupled tosaid coupler link at a third joint and coupled to said support frame ata fourth joint, said drive link is pivotable relative to said couplerlink about said third joint, said drive link is pivotable relative tosaid support frame about said fourth joint, said third joint is movablerelative to said support frame, and said fourth joint is fixed relativeto said support frame; and a pedal coupled to said coupler link at afifth joint, said fifth joint is movable relative to said support frame;and wherein a four-bar linkage is formed by said support frame, saididler link, said coupler link, and said drive link and constrainsmovement of said fifth joint to a linear travel path in a forwarddirection and a rearward direction.
 2. The rudder control apparatus ofclaim 1 wherein a ratio of a length L1 of said coupler link between saidthird joint and said fifth joint and a length L2 of said drive linkbetween said third joint and said fourth joint is 1:1.
 3. The ruddercontrol apparatus of claim 1 wherein said linear travel path is parallelto a horizontal plane.
 4. The rudder control apparatus of claim 1wherein said linear travel path is disposed at an angle of at most 10degrees relative to a horizontal plane.
 5. The rudder control apparatusof claim 1 wherein a ratio of a length L1 of said coupler link betweensaid third joint and said fifth joint and a length L3 of said couplerlink between said second joint and said third joint is 1:1.
 6. Therudder control apparatus of claim 1 wherein: said pedal is pivotablerelative to said coupler link about said fifth joint and is furthercoupled to a brake system; and pivotal movement of said pedal relativeto said coupler link about said fifth joint operates said brake system.7. The rudder control apparatus of claim 1 wherein a location of saidforth joint relative to said support frame is adjustable to change aneutral position of said pedal in said forward direction or said aftdirection.
 8. The rudder control apparatus of claim 1 wherein: saiddrive link is coupled to said rudder control device at a sixth joint,said sixth joint is movable relative to said support frame; linearmovement of said fifth joint along said linear travel path in saidforward direction and said rearward direction translates to pivotalmovement of said coupler link relative to said idler link about saidsecond joint; pivotal movement of said coupler link relative to saididler link about said second joint translates to pivotal movement ofsaid drive link relative to said coupler link about said third joint;and pivotal movement of said drive link relative to said coupler linkabout said third joint translates to movement of said sixth joint in adirection opposite of said fifth joint for control of side-to-sidemotion of a rudder coupled to said rudder control device.
 9. The ruddercontrol apparatus of claim 8 wherein: said fourth joint is locatedbetween said third joint and said sixth joint; and said sixth jointpartially revolves around said fourth joint in response to pivotalmovement of said drive link relative to said support frame about saidfourth joint.
 10. The rudder control apparatus of claim 9 wherein: saiddrive link comprises a drive link-first end and a drive link-second end,opposite to said drive link-first end; said third joint is located atsaid drive link-first end; said sixth joint is located at said drivelink-second end; and said fourth joint is located at an intermediatelocation between said drive link-first end and said drive link-secondend.
 11. The rudder control apparatus of claim 1 wherein: said secondjoint partially revolves around said first joint in response to pivotalmovement of said idler link relative to said support frame about saidfirst joint; and said third joint partially revolves around said secondjoint in response to pivotal movement of said coupler link relative tosaid idler link about said second joint.
 12. The rudder controlapparatus of claim 11 wherein said third joint is located between saidsecond joint and said fifth joint.
 13. The rudder control apparatus ofclaim 12 wherein: said coupler link comprises a coupler link-first endand a coupler link-second end, opposite to said coupler link-first end;said second joint is located at said coupler link-first end; said fifthjoint is located at said coupler link-second end; and said third jointis located at an intermediate location between said coupler link-firstend and said coupler link-second end.
 14. An aircraft comprising: anairframe comprising a support frame and rudder for control of yawmotion; a rudder control device operatively coupled to said rudder forcontrol of side-to-side motion of said rudder; and a laterally spacedapart pair of pedal assemblies, each one of said pair of pedalassemblies is coupled to said support frame and said rudder controldevice, and each one of said pair of pedal assemblies comprises: anidler link coupled to said support frame at a first joint, said idlerlink is pivotable relative to said support frame about said first joint,and said first joint is fixed relative to said support frame; a couplerlink coupled to said idler link at a second joint, said coupler link ispivotable relative to said idler link about said second joint, and saidsecond joint is movable relative to said support frame; a drive linkcoupled to said coupler link at a third joint and coupled to saidsupport frame at a fourth joint, said drive link is pivotable relativeto said coupler link about said third joint, said drive link ispivotable relative to said support frame about said fourth joint, saidthird joint is movable relative to said support frame, and said fourthjoint is fixed relative to said support frame; and a pedal coupled tosaid coupler link at a fifth joint, said fifth joint is movable relativeto said support frame; and wherein: a four-bar linkage is formed by saidsupport frame, said idler link, said coupler link, and said drive linkand constrains movement of said fifth joint to a linear travel path in aforward direction and a rearward direction; said drive link is coupledto said rudder control device at a sixth joint, said sixth joint ismovable relative to said support frame; linear movement of said fifthjoint along said linear travel path in said forward direction and saidrearward direction translates to pivotal movement of said coupler linkrelative to said idler link about said second joint; pivotal movement ofsaid coupler link relative to said idler link about said second jointtranslates to pivotal movement of said drive link relative to saidcoupler link about said third joint; and pivotal movement of said drivelink relative to said coupler link about said third joint translates tomovement of said sixth joint in a direction opposite of said fifth jointfor control of said side-to-side motion of said rudder.
 15. The aircraftof claim 14 wherein a first ratio of a length L1 of said coupler linkbetween said third joint and said fifth joint and a length L2 of saiddrive link between said third joint and said fourth joint and a secondratio of said length L1 and a length L3 of said coupler link betweensaid second joint and said third joint is 1:1.
 16. The aircraft of claim14 wherein: said second joint partially revolves around said first jointin response to pivotal movement of said idler link relative to saidsupport frame about said first joint; said third joint is locatedbetween said second joint and said fifth joint; and said third jointpartially revolves around said second joint in response to pivotalmovement of said coupler link relative to said idler link about saidsecond joint.
 17. The aircraft of claim 16 wherein: said coupler linkcomprises a coupler link-first end and a coupler link-second end,opposite to said coupler link-first end; said second joint is located atsaid coupler link-first end; said fifth joint is located at said couplerlink-second end; and said third joint is located at an intermediatelocation between said coupler link-first end and said couplerlink-second end.
 18. The aircraft of claim 17 wherein: said fourth jointis located between said third joint and said sixth joint; and said sixthjoint partially revolves around said fourth joint in response to pivotalmovement of said drive link relative to said support frame about saidfourth joint.
 19. The aircraft of claim 18 wherein: said drive linkcomprises a drive link-first end and a drive link-second end, oppositeto said drive link-first end; said third joint is located at said drivelink-first end; said sixth joint is located at said drive link-secondend; and said fourth joint is located at an intermediate locationbetween said drive link-first end and said drive link-second end. 20.The aircraft of claim 14 wherein said rudder control device comprises: arudder control push rod coupled to said drive link at said sixth joint;a rudder bar coupled to said rudder control push rod, said rudder bar ispivotable relative to said rudder control push rod in response tomovement of said sixth joint in said forward direction and said rearwarddirection.